1. Field of Invention
The present invention relates generally to alignment systems and, more particularly, is directed towards electro-optical alignment systems.
2. Description of the Prior Art
Manufacturing processes, such as those involving graphic arts, integrated circuits, printed circuit boards and assembly systems, require precise alignment among various components. Manual alignment systems are too time consuming and are subject to human error. Automatic alignment systems have been met with limited success primarily because they make indirect measurements relative to secondary references. Alignment systems of the type disclosed in U.S. Pat. Nos. 3,867,038 and 3,951,548 suffer from limitation that they are suitable only for closely spaced objects. A need exists for an improved electro-optical alignment system for alignment of objects that are not closely spaced.